Air pump in a hard disk drive (hdd)

ABSTRACT

An air pump for generating air pressure in a hard disk drive (HDD) including a rotor disposed inside the HDD. The rotor comprises a first air pressure generating feature. The air pump further includes a stator. The stator includes a second air pressure generating feature. The first air pressure generating feature corresponds with the second air pressure generating feature and the air pressure is generated at a location where the first air pressure generating feature rotates in proximity to the second air pressure generating feature.

CROSS-REFERENCE TO RELATED APPLICATION

U.S. patent application Ser. No. ______ entitled Aerostatic Sealing in aHard Disk Drive (HDD), by Ferdinand Hendriks, attorney docket numberHSJ920090050-US1, assigned to the assignee of the present invention,filed ______, and which is incorporated by reference in its entiretyherein.

FIELD

Embodiments of the present technology relate generally to the field ofhard disk drives.

BACKGROUND

Airflow caused by the rotation of disks in a hard disk drive (HDD)causes turbulence which can deleteriously affect the read/write functionof the HDD. Conventional technology attempts to limit the velocity ofthe airflow within the HDD, especially in the region of the read/writeheads, by placing aerodynamic parts (e.g., diverters, spoilers, damperplates, etc.) in close proximity to and/or in between the disks.However, there must always be a clearance between the aerodynamic partand the disks, because the disks will often fail if any part within theHDD physically contacts the disks. Passive clearances often occupy only50% of the disk/disk clearance or the disk/cover and disk/base castingclearance. Moreover, physical interaction between parts in a HDD cancause friction which can lead to mechanical failure of the interactingparts and also cause vibrations within the HDD.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a HDD, in accordance with an embodimentof the present invention.

FIG. 2 illustrates an example of aerostatic sealing, in accordance withan embodiment of the present invention.

FIG. 3 illustrates an example of aerostatic sealing, in accordance withan embodiment of the present invention.

FIG. 4 illustrates an example of an air pump, in accordance with anembodiment of the present invention.

FIG. 5 illustrates an example of an air pump, in accordance with anembodiment of the present invention.

FIG. 6 illustrates an example of an air pump, in accordance with anembodiment of the present invention.

The drawings referred to in this description should be understood as notbeing drawn to scale except if specifically noted.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to embodiments of the presenttechnology, examples of which are illustrated in the accompanyingdrawings. While the technology will be described in conjunction withvarious embodiment(s), it will be understood that they are not intendedto limit the present technology to these embodiments. On the contrary,the present technology is intended to cover alternatives, modificationsand equivalents, which may be included within the spirit and scope ofthe various embodiments as defined by the appended claims.

Furthermore, in the following description of embodiments, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present technology. However, the present technologymay be practiced without these specific details. In other instances,well known methods, procedures, components, and circuits have not beendescribed in detail as not to unnecessarily obscure aspects of thepresent embodiments.

In general, aerodynamic parts are configured to deflect, block, seal orotherwise inhibit airflow in the disk and actuator region andconsequently reduce turbulence in the disk and actuator region. Theremust always be a clearance between the disks and the aerodynamic partsbecause the disks can fail if the aerodynamic parts come into physicalcontact with the disks. However, the necessary clearance (a gap betweenthe aerodynamic part and the disks) provides a poor seal between theaerodynamic parts and the disks because there is considerable leakage.

Also, some parts within the HDD physically come into contact with eachother. The physical contact of parts can cause friction which can leadto mechanical failure of the contacting parts and may also add tovibrations within the HDD.

With reference now to FIG. 1, a schematic drawing of one embodiment ofan information storage system including a magnetic hard disk file or HDD110 for a computer system is shown, although only one head and one disksurface combination are shown. What is described herein for onehead-disk combination is also applicable to multiple head-diskcombinations. In other words, the present technology is independent ofthe number of head-disk combinations.

In general, HDD 110 has an outer housing 113 usually including a baseportion (shown) and a top or cover (not shown). In one embodiment,housing 113 contains a disk pack having at least one media or magneticdisk 138. The disk pack (as represented by disk 138) defines an axis ofrotation and a radial direction relative to the axis in which the diskpack is rotatable.

A spindle motor assembly having a central drive hub 130 operates as theaxis and rotates the disk 138 or disks of the disk pack in thecircumferential direction 140 relative to housing 113. An actuatorassembly 115 includes one or more actuator arms 116. When a number ofactuator arms 116 are present, they are usually represented in the formof a comb that is movably or pivotally mounted to base/housing 113. Acontroller 150 is also mounted to base 113 for selectively moving theactuator arms 116 relative to the disk 138. Actuator assembly 115 may becoupled with a connector assembly, such as a flex cable to convey databetween arm electronics and a host system, such as a computer, whereinHDD 110 resides.

In one embodiment, each actuator arm 116 has extending from it at leastone cantilevered integrated lead suspension (ILS) 120. The ILS 120 maybe any form of lead suspension that can be used in a data access storagedevice. The level of integration containing the slider 121, ILS 120, andread/write head is called the Head Gimbal Assembly (HGA).

The ILS 120 has a spring-like quality, which biases or presses theair-bearing surface of slider 121 against disk 138 to cause slider 121to fly at a precise distance from disk 138. ILS 120 has a hinge areathat provides for the spring-like quality, and a flexing cable-typeinterconnect that supports read and write traces and electricalconnections through the hinge area. A voice coil 112, free to movewithin a conventional voice coil motor magnet assembly is also mountedto actuator arms 116 opposite the head gimbal assemblies. Movement ofthe actuator assembly 115 by controller 150 causes the head gimbalassembly to move along radial arcs across tracks on the surface of disk138.

In one embodiment, HDD includes an upstream spoiler 160 (with aerostaticseals) for modifying air flow generated by the rotation of disks 138 andfor creating an aerostatic seal between itself and the disks 138.

Aerodynamic Devices for Aerostatic Sealing

FIG. 2 illustrates aerodynamic device 210 for aerostatic sealing in aHDD, in accordance with an embodiment of the present invention. FIG. 2depicts an aerodynamic device 210 for modifying air flow generated bythe rotation of disks 138 and for creating an aerostatic seal betweenitself and the disks 138. Aerodynamic device 210 includes an inlet port215 configured to receive pressurized air flow 240 and a plurality ofoutlet ports 220 configured to discharge the pressurized air flow 240from within the aerodynamic device.

In various embodiments, aerodynamic device 210 is any aerodynamic deviceconfigured to modify airflow in the HDD and located proximate at leastone disk in the HDD. For example, aerodynamic device 210 is a damperplate that is disposed between two disks. Aerodynamic device 210 can bea diverter which diverts airflow away (e.g., to a bypass channel) fromthe disk region.

Aerodynamic device can be a spoiler (e.g., upstream or downstream). Inone embodiment, aerodynamic device can be disposed in between at leasttwo disks of a plurality of disks. In another embodiment, aerodynamicdevice is disposed in between all of the disks in the HDD. In furtherembodiments, a plurality of aerodynamic devices are disposed in betweenat least two disks of a plurality of disks or disposed in between all ofthe disks in the HDD.

The pressurized air 240 that exits outlet ports 220 is dischargeddirectly at the disks 138. The pressurized air 240 discharged in thedirection of disks 138 increases the drag of the aerodynamic device andcauses an aerostatic seal 230 between the aerodynamic device 210 and thedisks 138. An aerostatic seal 230 is a non-contact seal. In other words,the discharged pressurized air 240 directed at the disks 138 allows fora mechanical clearance between the aerodynamic device 210 and the disks138 while also sealing the clearance. For example, turbulent air outsidethe disk region is prohibited by the aerostatic seal 230 from leakingpast to the disks and/or in between the disks through the clearance.Likewise, stable air flow in between the disks 138 is sealed in betweenthe disks by the aerostatic seal 230. Thus, making the HDD aerodynamicparts more effective.

It should be appreciated that any number of outlet and inlet ports 220can be formed in any orientation on the aerodynamic device 210. Forexample, outlet ports 220 can discharge pressurized air 240 orthogonalto the data surface of the disks 138. In another embodiment, outletports 220 can discharge pressurized air 240 parallel the data surface ofthe disks. It should be appreciated that the outlet ports can dischargepressurized air 240 at any angle with respect to the data surface of thedisks.

The pressurized air flow 240 is generated inside the HDD. In oneembodiment, the pressurized air flow 240 is generated by a pressuredifference inside the HDD. For example, pressurized airflow 240 cantravel from a location of high pressure to the inlet port 215, viaducting, if the pressure at the inlet port 215 is lower than that at thelocation of high pressure. In another embodiment, the pressurized airflow 240 is generated by an air pump inside the HDD, which is describedin detail below. It should also be appreciated that a suction (e.g.,flow from the outlet ports 220 to the inlet port 215) through the outletports 220 also creates an aerostatic seal 230 between the aerodynamicdevice 210 and disks 138.

FIG. 3 illustrates aerodynamic device 210 for aerostatic sealing in aHDD, in accordance with an embodiment of the present invention. Itshould be appreciated that the only difference between FIG. 3 and FIG. 2is that air is sucked through inlet ports 320 compared to beingdischarged through outlet ports 220 of FIG. 2. Accordingly, theaerostatic sealing illustrated in FIG. 3 is accomplished by an oppositeflow of air through aerodynamic device 210 as compared to FIG. 2. Inother words, aerostatic sealing is accomplished by air being suctionedor vacuumed into intake ports 320 and the suctioned air exits outputport 315. Therefore, aerostatic seal 230 is accomplished by vacuumpressure 340 that vacuums or sucks air into inlet ports 320 and out ofoutlet port 315.

Air Pump Inside HDD

FIGS. 4-6 illustrate air pumps that generate air pressure, in accordancewith an embodiment of the present invention. In various embodiments, theair pumps can be run in reverse and create a vacuum or suction pressure.FIG. 4 shows an exploded view of motor 400 that includes a motor spindleor rotor 410 and a base or stator 440. For purposes of brevity andclarity, only features applicable for the generation of air pressure inthe HDD are included. Rotor 410 includes an air pressure generatingfeature. For example, pocketed region 420 of the rotor 410 includes aseries of pockets 430 circumscribing the pocketed region. The stator 440includes a continuous channel 450 circumscribing the pocketed region ofthe stator. The channel 450 includes an inlet port 454 and an outletport 452.

The series of pockets 430 is opposed to the channel 450. The channel 450is an air pressure generating feature that corresponds to pockets 430.Accordingly, as the rotor 410 rotates with respect to stator 440, thepockets 430 entrain air through the inlet port 454. The air in eachpocket 430 progressively becomes compressed as it travels along thechannel 450. As the pockets of compressed air passes over the outletport 452, the pressurized air in the pockets discharges through theoutlet port 452. The pressurized air 460 can be delivered to any part ofthe HDD via ducting. In one embodiment, pressurized air 460 is 500 to2000 Pascals (Pa) or 50 to 200 millimeters (mm) H₂O. The pockets 430 canbe any shape (e.g., scallop) that allows for air circulate in thepockets and subsequently become compressed and exit the outlet port 452.It should be appreciated that the air pressure is generated at alocation where the air pressure generating feature of the rotor rotatesin proximity to the air pressure generating feature of the stator.

The clearance between the rotor 410 and the stator 440 can also causeleakage and accordingly loss of pressure. Leakage can be minimized bytechniques such as but not limited to labyrinth seals. In oneembodiment, the clearance between the rotor and the stator in thelabyrinth region is 0.2 mm.

In one embodiment, the rotor 410 and stator 440, in combination, act asa regenerative disk or friction pump. The pressure created by theregenerative disk or friction pump can cause an axial force on the rotorwhich is approximately equal to the average pressure on the stator 440.It should also be appreciated that the rotor 410 and stator 440, canwork in reverse.

FIG. 5 depicts an air pump 500, in accordance with an embodiment of thepresent invention. Air pump 500 includes a motor spindle or rotor 510, abase or stator 540, anti-vibration coupling 520 and wobbler 530. In oneembodiment, rotor 510 is a fluid dynamic bearing (FDB). Wobbler 530 isconfigured to convert the rotary motion of the rotor 510 into anorbiting motion. Anti-vibration coupling 520 is configured to reducevibration during the conversion of rotary motion into orbiting motion.In general, the wobbler 530 and the stator 540 have correspondinginterleaved scrolls (not shown) that pump, compress, or pressurize airthat is provided at intake 550. It should be appreciated that the rotor510 and wobbler 530, in combination, includes an air pressure generatingfeature (e.g., scroll). Also, the stator includes an air generatingfeature (e.g., scroll). Often, one of the scrolls is fixed, while theother orbits eccentrically without rotating, thereby trapping andpumping or compressing pockets of fluid between the scrolls. The vanegeometry of the scrolls (not shown) may be involute, archimedean spiral,or hybrid curves. It should be appreciated that the air pressure isgenerated at a location where the air pressure generating feature of thewobbler orbits in proximity to the air pressure generating feature ofthe stator.

Balancing of the motor 500 can be accomplished by operating two opposingpumps. In one embodiment, air pump 500 is a scroll pump. It should beappreciated that pressurized air generated by air pump 500 can bedelivered to any part of the HDD via ducting. In one embodiment, thepressurized air is 500 to 2000 Pa or 50 to 200 mm H₂O.

FIG. 6 depicts an air pump 600, in accordance with an embodiment of thepresent invention. Air pump 600 includes a rotor 610. In one embodiment,rotor 610 is a FDB. Rotor 610 includes an air pressure generatingfeature. For example, a plurality of buckets 620 circumscribing therotor 610. As rotor 610 rotates, the plurality of buckets 620 collectsair. The collected air is pressurized and discharges into a port 630. Inone embodiment, air pump 600 is a Pelton wheel. The pressurized airgenerated by air pump 600 can be delivered to any part of the HDD viaducting. In one embodiment, the pressurized air is 500 to 2000 Pa or 50to 200 mm H₂O. It should be appreciated that the air pressure isgenerated at a location where the air pressure generating feature of therotor rotates in proximity to the air pressure generating feature of thestator.

The air pressure created by air pumps depicted in FIGS. 4-6 can bedirected via ducting to anywhere inside the HDD. In one embodiment, theair pressure is the pressurized air flow 240 utilized to create theaerostatic seals 230, as described above. The air pumps, as with mostpumps, can work in reverse. In one embodiment, the air pressure createdby the air pumps depicted in FIGS. 4-6 is a vacuum pressure (e.g., 340)utilized to create the aerostatic seals 230, as described above.

Moreover, air pressure created within the HDD can also be used forlevitation of components inside the HDD. Typically, a slider 121 travelsover a load/unload ramp (not shown) when moving from a resting positionto a read/write position over the disk. In one embodiment, air pressurecan be directed to the slider 121, via ducting, as the slider travelsover the load/unload ramp and thereby levitating the slider 121.Accordingly, the levitation of the slider 121 will reduce friction andthereby reduce any vibrations due to the friction of the load/unloadramp.

Various embodiments of the present invention are thus described. Whilethe present invention has been described in particular embodiments, itshould be appreciated that the present invention should not be construedas limited by such embodiments, but rather construed according to thefollowing claims.

1. An air pump for generating air pressure in a hard disk drive (HDD)comprising: a rotor disposed inside said HDD, wherein said rotorcomprises a first air pressure generating feature; and a stator, whereinsaid stator comprises a second air pressure generating feature, whereinsaid first air pressure generating feature corresponds with said secondair pressure generating feature and said air pressure is generated at alocation where said first air pressure generating feature travels inproximity to said second air pressure generating feature.
 2. The airpump of claim 1, wherein said rotor comprises: a fluid dynamic bearing.3. The air pump of claim 1, wherein said air pressure is directed to anaerodynamic device and aerostatically seals said aerodynamic device withat least one disk.
 4. The air pump of claim 1, wherein said air pressureis directed to at least one component in said HDD and levitates said atleast one component.
 5. The air pump of claim 1, wherein said air pumpis selected from a group consisting of: a regenerative pump, a scrollpump or Pelton wheel.
 6. The air pump of claim 1, wherein said first airpressure generating feature comprises: a plurality of pocketscircumscribing said rotor at a pocketed region.
 7. The air pump of claim1, wherein said second air pressure generating feature comprises: achannel circumscribing said stator at a pocketed region.
 8. The air pumpof claim 1, wherein said air pressure comprises: an air pressurecomprising a range of 500 to 2000 Pascals (Pa).
 9. A hard disk drive(HDD) comprising: at least one magnetic disk; a rotor configured torotate said at least one magnetic disk, wherein said rotor comprises afirst air pressure generating feature; and a stator, wherein said statorcomprises a second air pressure generating feature, wherein said firstair pressure generating feature corresponds with said second airpressure generating feature and said air pressure is generated at alocation where said first air pressure generating feature travels inproximity to said second air pressure generating feature.
 10. The HDD ofclaim 9, wherein said air pressure is directed to an aerodynamic deviceand aerostatically seals said aerodynamic device with at least one disk.11. The HDD of claim 9, wherein said air pressure is directed to atleast one component in said HDD and levitates said at least onecomponent.
 12. The HDD of claim 9, wherein said air pressure isgenerated by an air pump wherein said air pump is selected from a groupconsisting of: a regenerative pump, a scroll pump or Pelton wheel. 13.The HDD of claim 9, comprising: a wobbler configured to convert a rotarymotion of said rotor to an orbital motion.
 14. The HDD of claim 9,wherein said first air pressure generating feature comprises: aplurality of pockets circumscribing said rotor.
 15. An air pump forgenerating a vacuum pressure in a hard disk drive (HDD) comprising: arotor disposed inside said HDD, wherein said rotor comprises a firstvacuum pressure generating feature; and a stator, wherein said statorcomprises a second vacuum pressure generating feature, wherein saidfirst vacuum pressure generating feature corresponds with said secondvacuum pressure generating feature and said vacuum pressure is generatedat a location where said first vacuum pressure generating featuretravels in proximity to said second vacuum pressure generating feature.16. The air pump of claim 15, wherein said vacuum pressure is directedto an aerodynamic device and aerostatically seals said aerodynamicdevice with at least one disk.
 17. The air pump of claim 15, whereinsaid air pump is selected from a group consisting of: a regenerativepump, a scroll pump or Pelton wheel.
 18. The air pump of claim 15,wherein said first vacuum pressure generating feature comprises: aplurality of pockets circumscribing said rotor at a pocketed region. 19.The air pump of claim 15, wherein said second vacuum pressure generatingfeature comprises: a channel circumscribing said stator at a pocketedregion.